Inhibition of fibrinolysis by CHO-TF. CHO cells (4 × 10⁵) expressing TF (A) and wild-type cells (B) were detached with EDTA, washed in PBS, and added for 3 hours at 37°C to a fibrin clot formed in the presence of plasminogen (0.5 μmol/L; lanes 3 and 4) or buffer (lanes 1 and 2). The wells were photographed and the size of the zone lysis evident in the center of each well was measured by scanning densitometry. The picture shown is representative of three experiments performed under identical conditions.